The term “whiteboard” commonly refers to any surface, typically glossy and most commonly colored white, where markings can be made. Whiteboards operate analogously to chalkboards, in that they allow markings that temporarily adhere to the surface of the board and that can be easily removed. Whiteboards often are employed in teaching environments (e.g., classrooms) as well as office environments, as they provide useful tools for communication in connection with pedagogy, problem solving, collaborative design, and the like. Whiteboards usually are made of plastic, melamine-coated pressboard, or steel coated with enamel or ceramic material, commonly referred to as “porcelain steel.” Steel whiteboards generally are magnetic, so magnets may be employed to affix notes or a magnetic eraser to them. Glass also provides a smooth, hard and erasable surface that has a surface quality suitable for whiteboard applications.
Instead of using chalk (as on chalkboards) to make the markings, a special whiteboard marker containing removable (non-permanent) ink having a variety of colors is typically used (these markers also are referred to as “dry-erase markers”). In general, whiteboard ink markings are less susceptible to external influences, such as water or accidental erasure, because the ink adheres slightly more strongly than chalk adheres to chalkboards. The ink is also less messy than chalk (which generates chalk dust during use and erasure).
In some applications, a whiteboard may be used as a projection screen, essentially serving as the background for a presentation generated by a projector (e.g., an overhead projector). In such an application, markings or writing may be made “on top of” the projected image so as to be superimposed on the image (e.g., blanks may be filled in or comments written on or adjacent to the projected material). Interactive whiteboards such as a PolyVision Walk-and-Talk, Promethean ACTIVboard, or SMART Board allow a computer display to be projected onto a whiteboard using a projector. In some instances however, projecting an image onto a whiteboard can produce a glare, making the image and/or superimposed markings difficult to read. Also, more generally, the white background of a whiteboard (with or without an image projected thereon) may cause contrast problems for people with vision impairment.
Most whiteboards provide temporary viewing of markings that can be easily erased if appropriate whiteboard markers are used. Some types of whiteboards, however, may be equipped with side-mounted scanners that allow the markings to be saved electronically for printing or viewing on a computer.
Whiteboards generally require a certain level of surface luminance to create a proper contrast ratio between the markings or writing made by an appropriate marker and the base surface of the whiteboard that provides a background. Typically, this is achieved “naturally” using lighting from an external light source that irradiates the whiteboard writing surface and is reflected outwards from it at a semi-diffuse angle of incidence. Thus, the appearance of the overall color scheme of conventional whiteboards and the contrast ratio between markings thereon and the background depends on this external lighting. Accordingly, the overall appearance of the whiteboard typically matches the ambient lighting.